SEWING MACHINES – FLEXIBLE MANUFACTURING, PROCESS CONTROL AND PLANNING

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SEWING MACHINES – FLEXIBLE MANUFACTURING, PROCESS CONTROL AND PLANNING

The industrial manufacturing of sewn products has always been one of the critical processes of the textile chain concerning quality assurance. Assuring the appropriate set-up and operation of all the machines, and thus the final seam quality, is a very complex task. Traditionally, this task is accomplished by empirical methods, with machine setting and quality control relying on the skills of operators and technicians. In this work, an approach to a more knowledge-based and integrated process planning and control is presented. A system was developed to measure and analyze the most important mechanical effects occurring during high-speed sewing.

Singer Merritt Sewing Machines

To address some of the problems stated previously, in particular the quick response to small production orders, several new production organization methods have been devised. These are based on higher flexibility and interchangeability of the operators, smaller production units and batch sizes, and higher mobility of the production equipment. But the simple reorganization of production cannot address all issues: VS Enterprises the variables related to the production process itself are still not controlled. Set-up of the machines is empirical and thus inaccurate and time-consuming. Initial set-up is maintained during operation regardless changing sewing conditions. Quality is assessed by visual inspection, often causing defective parts to pass unnoticed or to be detected very late. The approach proposed in this work relies on the evaluation and analysis of the relevant sewing parameters and their relation to quality problems and machine set-up variables. This integrated approach has enabled the development of methods to automatically detect sewing defects and seam quality, and to propose control methods for certain machine adjustments.

The objectives are therefore twofold. On one hand, they are directed to the development of monitoring and control devices for the machines, enabling them to adapt to variable sewing conditions and detect defective sewing conditions automatically. On the other hand, they aim at the establishment of testing methods and equipment for pre-production analysis of fabric “sewability”.

The tools developed in this work for sewing parameter analysis cover a comprehensive series of aspects of seam production efficiency. For all of the machine’s subfunctions, it is possible to obtain quantitative information describing aspects related to seam quality and localized defects. The productivity of the experimental work has been greatly boosted by the easy-to-use functions of the software. A series of experiments have been devised to examine the relevant sewing variables, considering varying sewing conditions. These experiments have been tailored to allow studies targeted at machine adjustments and the properties of materials, threads and needles. [[1],[4],[6]] This research is essential to the development of control and monitoring systems to render the machines adaptive and selfmonitored, thus increasing their flexibility and quality of the final product.